Virtual and augmented reality systems and methods

• US 10,739,593 B2
• Filed: 02/27/2017
• Issued: 08/11/2020
• Est. Priority Date: 02/29/2016
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Cheng, Hui-Chuan
• Primary Examiner(s): Thomas, Brandi N
• Application Number:
  US15/443,002
• Publication Number:
  US 20170248790A1
• Time in Patent Office: 1,261 Days
• Field of Search: 359237, 359619-633
• CPC Class Codes: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0185 Displaying image at variable distance
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/1006 for splitting or combining different wavelengths G02B27/1086, G02B27/141 take precedence
• CPC Class Codes: G02B 27/141 using dichroic mirrors
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area

Abstract

An imaging system includes a light source configured to generate a light beam. The system also includes first and second light guiding optical elements having respective first and second entry portions, and configured to propagate at least respective first and second portions of the light beam by total internal reflection. The system further includes a light distributor having a light distributor entry portion, a first exit portion, and a second exit portion. The light distributor is configured to direct the first and second portions of the light beam toward the first and second entry portions, respectively. The light distributor entry portion and the first exit portion are aligned along a first axis. The light distributor entry portion and the second exit portion are aligned along a second axis different from the first axis.

Claims

1. An imaging system, comprising:

a light distributor having multiple beam splitters and splitting a light beam from a light source into at least a first portion and a second portion;

a first light guiding optical element (LOE) having a first set of gratings and a first entry portion and propagating the at least the first portion of the light beam for defining a first focal plane, wherein the first set of gratings at least partially overlaps a first shutter along a first direction in which the first portion of the light beam propagates to receive the first portion of the light beam from the light distributor through the first shutter of the imaging system;

a second light guiding optical element (LOE) having a second set of gratings and a second entry portion and propagating the at least the second portion of the light beam for defining a second focal plane, wherein the second set of gratings receives at least a portion of the second portion of the light beam from the light distributor through a second shutter, wherein

the first LOE and the second LOE are arranged as stacked LOEs that creates an image at one or more depth planes, each of the stacked LOEs displays an image that appears to originate from a particular depth plane of the one or more depth planes, and the second set of gratings at least partially overlaps a second shutter along a second direction in which the at least the portion of the second portion of the light beam propagates to receive the at least the portion of the second portion of the light beam through the second shutter; and

the light distributor comprising a light distributor entry portion, a first exit portion, and a second exit portion, wherein

the light distributor directs, using at least a first beam splitter of the multiple beam splitters, the first portion of the light beam toward the first entry portion of the first LOE through the first exit portion of the light distributer,

the light distributor directs, using at least a second beam splitter of the multiple beam splitters, the second portion of the light beam toward the second entry portion of the second LOE through the second exit portion of the light distributer using at least the multiple beam splitters,

the light distributor entry portion and the first exit portion are aligned along a first optical axis, and

the light distributor entry portion and the second exit portion are aligned along a second optical axis orthogonal to the first optical axis.

2. The system of claim 1, wherein the first and second light guiding optical elements and the light distributor are configured such that:

when the light beam interacts with the first exit portion, a first exit beamlet of the light beam exits the light distributor and enters the first light guiding optical element via the first entry portion, and

when the light beam interacts with the second exit portion, a second exit beamlet of the light beam exits the light distributor and enters the second light guiding optical element via the second entry portion.

3. The system of claim 1, further comprising first and second shutters configured based at least in part upon convergence or divergence of the light when the light beam interacts with at least one beam splitter of the multiple beam splitters, a shutter, or an in-coupling grating to selectively interrupt first and second light paths between first and second exit portions and first and second entry portions, respectively.

4. The system of claim 1, wherein the first and second light guiding optical elements are disposed on opposite sides of the light distributor.

5. The system of claim 1, further comprising a focusing diffractive optical element disposed between the first and second light guiding optical elements, wherein

the focusing diffractive optical element is configured to focus the second exit beamlet of the light beam toward the second entry portion of the second light guiding optical element.

6. The system of claim 1, wherein the multiple beam splitters comprises a first beam splitter and a second beam splitter, the first exit portion comprises the first beam splitter having a first size, and the second exit portion comprises the second beam splitter.

7. The system of claim 6, wherein the first and second beam splitters have different sizes, wherein the first size of the different sizes is configured based at least in part upon at least one of a total number of LOEs in the system, a size of a field of view provided by the system, an exit pupil size, or a size of an in-coupling grating in the system.

8. The system of claim 7, wherein the first and second entry portions have different sizes corresponding to the different sizes of the first and second beam splitters.

9. The system of claim 6, where the light distributor entry portion comprises a receiving beam splitter configured to divide the light beam into first and second split beamlets that are respectively directed to the first and second beam splitters.

10. The system of claim 9, wherein the receiving beam splitter comprises a dichroic beam splitter.

11. The system of claim 10, wherein the first split beamlet is configured to redirect green light and the second split beamlet is configured to redirect red and blue light.

12. The system of claim 9, wherein the receiving beam splitter comprises a polarizing beam splitter, and the light beam comprises polarized light.

13. The system of claim 1, wherein the first set of gratings and the second set of gratings are configured based at least in part upon a first shutter location of the first shutter and a second shutter location of the second shutter.

14. The system of claim 12, wherein the light distributor has a retardation filter that is configured to change a polarization of a portion of the light beam and is located between a first beam splitter and a second beam splitter in the light distributor, and the second beam splitter is configured to redirect the portion of the light beam, the polarization of which has been changed, while allowing a remaining portion of the light beam to proceed through the second beam splitter.

15. The system of claim 14, wherein the multiple beam splitters in the light distributor are connected by at least one in-coupling beam splitter, and the at least one in-coupling beam splitter is located between the multiple beam splitters.

16. The system of claim 9, wherein the receiving beam splitter is an X-cube beam splitter.

17. The system of claim 6, the multiple beam splitters further comprising a third beam splitter disposed along the first optical axis such that the first beam splitter is located between the second light distributor beam splitter and the third beam splitter.

18. The system of claim 17, wherein the first beam splitter comprises a dichroic beam splitter that is configured to divide the light beam into first and second beamlets, and the first and third beam splitters are configured to direct the first beamlet toward the first entry portion of the first LOE and to direct the second beamlet toward the third beam splitter.

19. The system of claim 18, wherein the first and second shutters are configured such that only one beamlet of the first and the second beamlets passes through a corresponding shutter of the first and the second shutters at a time.

20. The system of claim 17, wherein the first beam splitter comprises a polarizing beam splitter, and the light beam comprises polarized light.

21. The system of claim 20, wherein the first set of gratings and the second set of gratings are configured to be offset from one another along a first direction relative to a second direction in which the stacked LOEs are stacked.

22. The system of claim 20, wherein the light distributor comprises a retardation filter located between the first beam splitter and the second beam splitter and configured to change a polarization angle of a portion of the light beam.

23. The system of claim 22, wherein the retardation filter is configured to change the polarization angle of only red light while leaving the polarization angle of blue light unchanged.

24. The system of claim 1, wherein the second optical axis is parallel to the stacked LOEs.